The invention relates to a cutting device for arranging a cut around the anus of a slaughtered animal, which cutting device comprises:
a positioning rod for insertion into the anus of a slaughtered animal;
a rotatably drivable cylindrical beaker-shaped knife which is placed coaxially round the positioning rod and whereof the free end is provided with a cutting edge; and
pressure means and suction means comprising a conduit extending through the positioning rod, debouching on the peripheral surface of the positioning rod at a distance from the cutting edge and connectable to a pressure source and an underpressure source respectively for generating an overpressure and an underpressure respectively at the position of the debouchment of that conduit.
Such a device is known from NL-A-73 06059. In this known device a conduit debouches on the peripheral surface of the positioning pin which is alternately connectable to an underpressure source and a pressure source. The cut away anus of a slaughtered animal, particularly poultry, can first be sucked fixedly and subsequently removed form the device by energizing the pressurized air source.
The drawback to the known device can be that feces still come out of the anus, whereby the sterility of the slaughtered animal is lost. Feces that may still be adhering to the positioning rod can also find their way onto or into the slaughtered animal. This could be prevented by removing the cutting device very carefully. In the rather rough and ready slaughterhouse business this is however not really possible.
It is therefore the object of the invention to provide a cutting device of the type referred to in the preamble wherein it is ensured that the slaughtered animal is not contaminated during removal of the cutting device.
This is achieved according to the invention with a device having a pressure conduit and a suction conduit, which conduits are connectable to a pressure source and an underpressure source respectively, which pressure conduit debouches on the peripheral surface of the positioning rod and which suction conduit debouches in the space bounded by the beaker-shaped knife.
The suction conduit can debouch on the inner surface of the knife or on the peripheral surface of the positioning rod.
In this latter case the device can have the feature that the pressure conduit and the suction conduit debouch at a mutual axial distance on the peripheral surface of the positioning rod.
It is noted that the debouchments of the conduits can take a multiple form and be placed for instance in distributed manner.
By actuating the pressure source which can generate a gaseous or liquid medium an overpressure can be excited in the space between the positioning rod and the rectum, whereby fecal remnants are pressed into the rectum. Fecal remnants arriving at the embouchement of the suction conduit can thus be removed from the space bounded by the knife. If desired, this removing can be stimulated by energizing the underpressure source. After completing the handling of the slaughtered animal the overpressure within the knife can attribute to a ready removing of the animal. It should be noted that the options given here are only alternatives subjected to the user's wishes.
When the cut is made the skin around the anus is held stretched, which has a positive effect on the cutting action. The overpressure generated inside the beaker-shaped knife by the pressure means can also ensure that fecal residues are transported to the suction means. This also reduces the risk of fecal residues dripping out of the beaker-shaped knife.
The device preferably has the feature that the or each debouchment of the pressure conduit is located between the free end of the positioning rod and the or each debouchment of the suction conduit.
A practical embodiment is that wherein the pressure conduit and the suction conduit extend in axial direction through the positioning rod in mutual coaxial relation.
This variant can be characterized by an axial bore in the positioning rod bounding the suction conduit and by a tube placed therein which bounds the pressure conduit and separates the pressure conduit from the suction conduit.
In order to prevent as far as possible damage to the anus of a slaughtered animal the device preferably has the feature that the free end of the positioning rod has a smooth, rounded shape. This embodiment can have the particular feature that the free end of the positioning rod has a rotation-symmetrical widening.
In a subsequent embodiment the device has the feature that the positioning rod has a rotation-symmetrical widening in the region of the debouchments of the pressure conduit and the suction conduit.
Advantageous is that alternative embodiment, in which the widening has a recess in the region of the or each debouchment of the pressure conduit. When the positioning rod is rotated in the anus the debouchment of the pressure conduit hereby remains clear thereof. This avoids damage to the rectum and the anus wall by the edges of the debouchments. At the suction mouth this problem does not occur since the anus wall has a more robust structure there in view of the presence of the sphincter muscle at that location and the transition to the exterior of the animal.
A simple structure is obtained with an embodiment in which the positioning rod and the knife are coupled fixedly to one another. The above description relating to the recessed location of the debouchment of the pressure conduit already relates thereto.
In order to counter imbalance the embodiment is recommended which has the feature that the rotational axis and the axis of inertia mutually coincide.
The invention will now be elucidated with reference to the annexed drawing, in which: